Approximately 1.25 million new cases of breast cancer are diagnosed each year. In a majority of these cases, there is an urgent need for surgery to remove the tumor and to excise the sentinel lymph nodes and inspect them histologically to determine whether the cancer has spread to other sites in the body. The sentinel lymph nodes are the first nodes to receive lymphatic drainage from the tumor. They are called this because they reliably alert the clinician to any cancer spread. A sentinel lymph node biopsy is a standard of care in breast cancer operations today.
Locating sentinel nodes during surgery is difficult. One method for locating the sentinel node is to inject a dark blue dye into the lymphatic system in the breast. The dye then disperses throughout the breast lymphatic system and the surgeon removes any colored nodes. This method is recognized as being error-prone.
An improved method involves injecting a radioactive dye into the lymph nodes. In a similar manner, the dye drains through the lymphatic system and the surgeon then uses a radiation detector to help locate the sentinel nodes. However, the use of radioisotopes presents a significant, and an expensive, logistical burden, because of the need to allocate the time and resources of a nuclear medicine radiologist in addition to the surgeon for what is otherwise a routine operation. Further many patients are reluctant to receive a radioactive injection. These factors become a significant barrier to the widespread adoption of the use of radioisotopes to locate the sentinel nodes.
In addition the ability to mark or tattoo a region is important to permit a surgeon to locate areas of interest. Most tattooing takes place on the surface of the skin or through the embedding of macro-objects such as staples in the tissue of interest. Unfortunately such surface tattooing only shows the surgeon the region of the surface below which the tissue of significance is located. It does not demark in the 3-D the location of the tissue. A way is needed to delineate, in 3-D, regions of interest for the surgeon.
Finally, metallic fragments dispersed through tissue are a frequent occurrence in combat and industrial accident related injuries. Finding these fragments are problematic for operating room surgeons attempting to repair tissue damage.
The present invention solves these issues.